Chris Harper-Mercer, 26, shot dead nine people at Umpqua Community College in OregonMyspace

Chris Harper-Mercer, the 26-year-old identified locally as the gunman who shot nine people dead at a college in the US state of Oregon, was an introverted young man with an interest in conspiracy theories and previous mass shootings, people who knew him and trails he left online revealed.

Harper-Mercer lived only a few miles from the Umpqua Community College, where he opened fire on students before being shot dead by police. At least seven people were wounded. Witnesses said he walked in the institute with a long gun and two handguns and asked people their name and religion before embarking on the deadly rampage.

"'Are you a Christian?' he would ask them, and 'If you are a Christian then stand up,' and they would stand up. He'd say: 'Because you are a Christian you're going to see God in about one second,' and then he shot and killed them," the father of eyewitness Anastasia Boylan, 18, told CNN.

Neighbours described him as a withdrawn character. "[He] seemed really unfriendly," Bronte Harte, who lived below the apartment flat Harper-Mercer shared with his mother in Winchester, told AP, adding the man would "sit by himself in the dark on the balcony with this little light".

Causes for his actions were not immediately clear. A law enforcement official described the gunman to the New York Times as "an angry young man who was very filled with hate".

Although, according to witnesses, religion seemed to have played a role in the dynamic of the shooting, an online dating account on website Spiritualpassions listed Harper-Mercer's religious views as: "Not Religious, Not Religious, but Spiritual". The same profile said he looked for a "Pagan, Wiccan" or similarly non-religious date.

His father, who lives in Tarzana, California, told local media he was shocked at his son's crime, adding it was a "devastating day" for him before demanding media respect his family's privacy. Harper-Mercer relocated from Torrance, California, to Oregon in 2013, the local Daily Breeze newspaper reported, adding he graduated there from a school for students with learning abilities and emotional issues.

On Spiritualpassions, Harper-Mercer listed his political views as conservative, republican, his ethnicity as mixed and his interests as internet, killing zombies, movies, reading and music, particularly industrial, punk and rock.

Another account in his name on Myspace featured a profile picture where he is holding what appears to be a rifle and was packed with postings of masked gunmen and references to the Irish Republican Army (IRA), the paramilitary group that led a violent independence struggle with religious undertones in Northern Ireland. Some unconfirmed reports in the US claimed Mercer was born in England and later moved across the Atlantic.

A blog he held on the website Kickass Torrents showed a grim interest in recent shootings that made headlines in the US. "On an interesting note, I have noticed that so many people like him are all alone and unknown, yet when they spill a little blood, the whole world knows who they are," he wrote, commenting on the murder on live TV of a reporter and her cameraman by a former colleague in Virginia in August.

"A man who was known by no one, is now known by everyone. His face splashed across every screen, his name across the lips of every person on the planet, all in the course of one day. Seems the more people you kill, the more your're [sic] in the limelight".

An email address believed to be Mercer's was also linked to an account under the nickname of Lithium_Love, on another file-sharing website, kat-ph.proxy-x.com. There, earlier this week, he posted a BBC documentary on the 2012 mass shooting at a school in Newtown, Connecticut, titled "Surviving Sandy Hook".

The upload was the last of a series, which included conspiracy-theory-based documentaries on the Illuminati as wells soft pornography and copies of Phenomena, a magazine on paranormal activities, UFOs and the occult.

The incident reignited the debate on lax US gun laws. "I suspect this is going to start a discussion across the country about how community colleges prepare themselves for events like this," said the targeted college's former president, Joe Olson.